The present invention relates to a packaged product in which an article, such as a bag, pouch, or casing, is used to package a product, such as food. The invention also relates to a process for making the packaged product according to the present invention.
Injecting fresh meat with liquid, such as brine, is a means to tenderize the meat. The brine interacts with the muscle proteins, with the resulting liquid mixture exuding from the meat. During packaging, the liquid which is on the surface of such injected meat products is a blend of the injected brine, muscle proteins, and natural juices and blood from the meat product. This liquid blend tends to smear onto the packaging film in the region to be sealed. The liquid blend is difficult to seal through. We have analyzed the seal strength of seals made under various conditions, and have discovered that the strength of seals made through the liquid blend can be even more than 80% less than the strength of seals made without the liquid blend being present in the seal area while the seal is made.
While some processors have successfully solved this weak-seal problem with equipment and line layouts which prevent the liquid blend from depositing on the seal area, other processors continue to have significant problems. Moreover, it has been found that high-shrinking bags exacerbate the seal failure problem. That is, as the bag shrinks, the seal contacts the product which puts pressure on the seal, which can cause seal failure as the seal shrinks tightly up against the product.
One solution to the seal failure problem has been to provide an oversized shrink bag, so that the seal is made far enough from the product that the shrinkage of the bag does not result in the seal contacting the product within the bag. Although this may reduce the seal failure problem, it causes other problems. More particularly, it produces a packaged product of lesser aesthetic value due to excess film extending outward from the product being packaged. Secondly, the excess film provides an envelope which tends to collect juices from the meat product, which are unsightly and also exhibit an accelerated spoilage rate relative to the remainder of the meat product. It would also be desirable to avoid the seal failure problem while also avoiding the problems of diminished aesthetic appearance due to excess film, unsightly juice accumulation in the envelope of the excess film, and reduced shelf life due to accelerated spoilage rates caused by the juice which accumulates in the envelope of the excess film. The inventors of the present invention have arrived at a solution to these problems.
We have discovered that seal failure rates can be dramatically reduced for the packaging of a boneless meat product in which the meat has been injected with brine, without using an oversized bag and while providing a package in which the film is shrunk tightly against the meat product. We have discovered that bags made from particular films can be sealed through a brine-containing liquid blend, with significantly fewer seal failures even after the film is shrunk tightly against the boneless meat product. Moreover, it has been found that the use of lower shrink tension and/or lower free shrink can assist in reducing the seal failure due to the seal pulling down tightly against the product being packaged during shrinkage of the film after it is sealed around the product. Our invention enables us to package a product using a bag which is sized closer to the size of the product, thereby providing a final packaged product with an appearance which is of greater aesthetic appeal, i.e., versus the use of an oversized bag.
Using a highly abusive test, we have assessed a seal failure rate of about 66 percent using bags which are currently in commercial use for the packaging of brine-injected boneless pork products. However, through the use of bags made from films of particular polymers (especially metallocene-catalyzed ethylene/alpha-olefin copolymers in the seal layer), as well as by providing the film with a relatively low free shrinkage (and/or substantially lesser shrink tension) in a direction which, in general, is perpendicular to the seal made through the liquid blend, we have discovered that we can reduce the seal failure rate to a level as low as 26 percent, using the same highly abusive test. This is a 60 percent reduction in seal failure rate, using a test we believe to be significantly more abusive than the actual conditions of use of the packaged products. In view of the substantial improvement in seal integrity during our highly abusive testing, we believe that in commercial use our packaged products will exhibit a seal failure rate which is a substantial improvement over the seal failure rate currently being experienced in the commercial market.
As a first aspect, the present invention is directed to a packaged product comprising: (A) a boneless food product comprising at least one member selected from the group consisting of meat and cheese, the food product having a free liquid additive thereon; and (B) a film article which is both surrounding and in contact with both the food product and the free liquid. The film article exhibits a Standard Drop Test failure rate of less than 60 percent; more preferably, less than 55 percent; still more preferably, less than 50 percent; yet still more preferably, less than 45 percent; still more preferably, less than 40 percent, still more preferably, less than 35 percent; still more preferably, less than 30 percent; still more preferably, less than 25 percent; still more preferably, less than 20 percent; still more preferably, less than 15 percent.
Preferably, the film article comprises a heat-shrinkable film. Preferably, the film is a multilayer film comprising a seal layer comprising a homogeneous ethylene/alpha-olefin copolymer. Preferably, the film has a thickness of from about 1.5 to 3 mils; more preferably, from about 1.8 to 2.7 mils; still more preferably, from about 2 to 2.4 mils. Preferably, the film has a free shrink at 185xc2x0 F. of from about 15 to 60 percent in at least one direction; more preferably, from about 20 to 50 percent. Preferably, the film has a shrink tension at 185xc2x0 F. of from about 50 to 350 pounds per square inch (i.e., xe2x80x9cpsixe2x80x9d) in a first direction, and from about 300-1000 in a second direction; more preferably, from about 100 to 200 psi the first direction, and from about 360 to 600 psi in the second direction. Shrink tension is measured in accordance with ASTM D 2838, the entirety of which is hereby incorporated by reference thereto.
If the film article is an end-seal bag, preferably the first direction is the machine direction (i.e., longitudinal direction), so that a seal made through the liquid blend is forced against the product by the shrink tension in the first direction. Likewise, if the film article is a side-seal bag, preferably the first direction is the transverse direction. Preferably, the second direction has a shrink tension of at least about 120 percent of the shrink tension of the first direction; more preferably, from about 150 to 2000 percent of the shrink tension of the first direction; still more preferably, from about 150 to 350 percent of the shrink tension of the first direction; and, yet still more preferably, from about 150 to 300 percent of the shrink tension of the second direction.
Preferably, the multilayer film has a seal layer comprising at least one member selected from the group consisting of polyolefin, polyamide, polyester, polyvinyl chloride, and ionomer; more preferably, homogeneous ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer (especially ethylene/vinyl acetate copolymer), and ionomer. Preferably, the seal layer comprises homogeneous ethylene/alpha-olefin copolymer in an amount of at least about 90 weight percent. A particularly preferred seal layer comprises homogeneous ethylene/alpha-olefin copolymer in an amount of about 80 percent, based on layer weight, and linear low density polyethylene in an amount of about 20 percent, based on layer weight. Preferably, the multilayer film further comprises an O2-barrier layer, which in turn preferably comprises at least one member selected from the group consisting of ethylene/vinyl alcohol copolymer, polyvinylidene chloride (PVDC), polyalkylene carbonate, polyamide, polyethylene naphthalate, polyester, polyacrylonitrile. Preferably, the film comprises a crosslinked polymer network, which is preferably obtained by irradiation of one or more layers of the film. If the multilayer film comprises an O2-barrier layer, preferably the film further comprises one or more adhesive layers (i.e., xe2x80x9ctiexe2x80x9d layers) to enhance interlayer adhesion of the various film layers to one another.
Preferably, the free liquid additive comprises brine. Preferably, the brine is present in an amount of from about 1 percent to 30 percent, based on the weight of the product; more preferably, from about 5 to 25 percent; still more preferably, from about 6 to 20 percent; yet still more preferably, from about 10 to 12 percent, or from about 16 to 18 percent. Preferably, the food product comprises meat. Preferably, the meat product comprises at least one member selected from the group consisting of poultry, pork, beef, lamb, goat, horse, and fish; more preferably, at least one member selected from the group consisting of poultry, pork, beef, and lamb; still more preferably, at least one member selected from the group consisting of pork and beef, yet still more preferably, brine-injected pork.
As a second aspect, the present invention is directed to a packaging process comprising: (A) making a film article having an open top, (B) placing into the film article a boneless food product having an added liquid thereon, and (C) heat sealing across the open top of the film article. The film article comprises at least one member selected from the group consisting of a bag, a pouch, and a casing. When being placed into the film article, the boneless food product deposits liquid contamination onto a region of an inside surface of the film article before the film article is sealed across the top thereof The blend comprises the added liquid. Upon sealing across the top of the film article and through the liquid blend, a packaged product is formed. The film article exhibits a Standard Drop Test failure rate of less than 60 percent.
Preferably, the process further comprises evacuating atmosphere from within the film article after the boneless food product is placed into the film article but before the heat sealing across the open top of the film article. Preferred films, food products, and added liquids are as set forth above in the first aspect of the present invention. Preferably, brine is injected into a boneless meat product before the meat product is placed into the film article. Preferably, the film article comprises at least one member selected from the group consisting of an end-seal bag, a side-seal bag, a casing, and a pouch, with the first direction being parallel to a length of the article, and the second direction being perpendicular to the length of the article. If the first direction is a machine direction and the second direction is a transverse direction, preferably the article is an end-seal bag, casing, or pouch; if the first direction is the transverse direction and the second direction is the machine direction, preferably the article is a side-seal bag. If the film article is a casing, it can be either seamless or backseamed. If the film article is a pouch, it can be an L-seal pouch or a U-seal pouch.
As a third aspect, the present invention is directed to a packaged product comprising a bone-in meat product having a free liquid additive thereon, and a film article which is both surrounding and in contact with both the bone-in meat product and the free liquid. The film article exhibits a Standard Drop Test failure rate of less than 30 percent, More preferably, the film article exhibits a Standard Drop Test failure rate of less than 25 percent; still more preferably, less than 20 percent, yet still more preferably, less than 15 percent; and still more preferably, less than 10 percent. Preferred films are as described above in the first and second aspects of the present invention. Preferred boneless meat products include bone-in beef, pork, lamb, foul (including chicken, turkey, etc.), fish, goat, and horse.